engleski

Comparability of Methods for Assessing Wet Gluten Content of Wheat Flour

Gluten is the composite part of wheat flour responsible for rheological properties of the dough and quality of the finished product. The content of wet gluten in wheat flour is determined by the method of manual gluten washing and the accuracy of the obtained results significantly depends on the analyst’s experience. Since 1994, the fully automated Gluten Index Method has been used to determine the gluten content of flour. Accuracy, precision and comparability of the method by manual gluten washing and the Gluten Index Method were studied using samples of wheat flour of pure wheat cultivars grown in the region of the Republic Croatia (28 samples). The performed study showed that there is no statistically significant difference between the tested methods, i.e. that there is no statistically significant difference between the measured mean values of wet gluten contents assessed by the Gluten Index Method and by the method of manual gluten washing (t calc. = 1.170< t tab. (0.05) = 1.675) and none between the variances of the same method (F calc. = 1.355< F tab.(0.05) = 1.905). The tested methods are of the same degree of accuracy. The model of simple linear regression with assessed parameters using the method of least squares for the wet gluten content determined by the Gluten Index method is: WGC GI = 1.329 + 1.1003*WGC MW. The coefficient of regression variation amounted to 5.357%, the estimated regression variance to 2.533, and the standard error of estimation to 1.592 indicating good representation of the model. For the analyzed regression model, the coefficient of linear correlation amounts to 0.945 and indicates to high correlation between the wet gluten contents determined by different methods. The coefficient of determination r 2 for the analyzed model amounts to 0.893 meaning that, using the suggested model, one could explain 89.30% of deviation. The corrected coefficient of determination amounted to 0.889. The Gluten Index Method can therefore be recommended for determination of wet gluten content in flour.

wet gluten gluten index method

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